This invention generally relates to a hydraulic bicycle system. More specifically, this invention relates to a hydraulic bicycle component and/or a hydraulic hose assembly that are used in a hydraulic bicycle system.
An example of a hydraulic bicycle system is a hydraulic brake system. A typical hydraulic brake system includes a brake hand lever assembly that is fluidly coupled to a brake caliper assembly by a hydraulic hose assembly. To actuate the brake, the rider squeezes the hand lever. Through a cam or other linkage, this squeezing motion advances a primary piston down the axis of a hydraulic primary cylinder. This pressurizes and displaces hydraulic fluid in the chamber forward of the piston head. The chamber, and its fluid content, is in fluid communication with the fluid-filled hydraulic hose assembly by way of a hand lever assembly connection port. A remote end of the hydraulic hose assembly in turn is connected to another connection port on the housing of the caliper assembly. The caliper assembly contains at least one, and may contain several, secondary cylinders with secondary pistons that slide along the respective axes of their cylinders. This latter piston movement will be translated by the caliper assembly into a clamping force on the rim or disk. Hence, advancement of the piston within the primary cylinder pressurizes and displaces hydraulic fluid ahead of it, and this results in hydraulic fluid in the caliper assembly housing advancing piston(s) within their respective secondary cylinders.
An issue peculiar to hydraulic brake systems is the prevention or minimization of the introduction of air into the hydraulic brake lines, cylinders and fluid chambers. A consideration which hydraulic bicycle brake systems share with other hand-actuated bicycle controls is to reduce, as much as possible, the aerodynamic drag of the cables and hoses. To minimize such drag, designers seek to route the lines through the bicycle frame, through frame holes that are made as small as possible. In order to route a hydraulic brake hose, the hose must be separated from either the brake lever assembly or the brake caliper assembly and fed through frame entry and exit points. Given that the hydraulic brake system requires full fluid volume and a minimal quantity of entrapped air to function properly, the process of disconnecting and reconnecting the brake hose to the brake assembly(ies) should minimize the loss of brake fluid and entry of air into the system.